Analyzer

Diagnostic ID: RS1034: Prefer 'IsKind' for checking syntax kinds

Analyzer source

NuGet Package: Microsoft.CodeAnalysis.Analyzers

Version: 3.3.3 (Latest)

Describe the bug

The code fix for RS1034 applies a code change that leads to malfunctions at runtime.

Steps To Reproduce

git clone https://github.com/microsoft/vs-threading.git
cd vs-threading
git checkout 07ca567041a077f2814f6b096237a9d76884c5b0

Change FixUtils.cs L104 to:

hasReturnValue = (method.ReturnType as PredefinedTypeSyntax)?.Keyword.Kind() != SyntaxKind.VoidKeyword;

Expected behavior

-hasReturnValue = (method.ReturnType as PredefinedTypeSyntax)?.Keyword.Kind() != SyntaxKind.VoidKeyword;
+hasReturnValue = (method.ReturnType as PredefinedTypeSyntax)?.Keyword.IsKind(SyntaxKind.VoidKeyword) is not true;

(or some other equivalent transaction.

Actual behavior

-hasReturnValue = (method.ReturnType as PredefinedTypeSyntax)?.Keyword.Kind() != SyntaxKind.VoidKeyword;
+hasReturnValue = !(method.ReturnType as PredefinedTypeSyntax).IsKind(SyntaxKind.VoidKeyword);

The transaction here is not equivalent in behavior. Note the drop of the .Keyword in the expression, which leads to the IsKind to always return false.